The effect of halofugınone and pirfenidone on wound healing in experimental glaucoma filtration surgery

Pirfenidone use in fibrotic diseases: What do we know so far?

BACKGROUND

Pirfenidone has demonstrated significant anti-inflammatory and antifibrotic effects in both animal models and some clinical trials. Its potential for antifibrotic activity positions it as a promising candidate for the treatment of various fibrotic diseases. Pirfenidone exerts several pleiotropic and anti-inflammatory effects through different molecular pathways, attenuating multiple inflammatory processes, including the secretion of pro-inflammatory cytokines, apoptosis, and fibroblast activation.

OBJECTIVE

To present the current evidence of pirfenidone's effects on several fibrotic diseases, with a focus on its potential as a therapeutic option for managing chronic fibrotic conditions.

FINDINGS

Pirfenidone has been extensively studied for idiopathic pulmonary fibrosis, showing a favorable impact and forming part of the current treatment regimen for this disease. Additionally, pirfenidone appears to have beneficial effects on similar fibrotic diseases such as interstitial lung disease, myocardial fibrosis, glomerulopathies, aberrant skin scarring, chronic liver disease, and other fibrotic disorders.

CONCLUSION

Given the increasing incidence of chronic fibrotic conditions, pirfenidone emerges as a potential therapeutic option for these patients. However, further clinical trials are necessary to confirm its therapeutic efficacy in various fibrotic diseases. This review aims to highlight the current evidence of pirfenidone's effects in multiple fibrotic conditions.

Aqueous Humor Growth Factor Levels and Trabeculectomy Outcomes in Primary Open-Angle Glaucoma Patients: A 2-Year Prospective Study

Purpose

Maintenance of a filtering bleb is essential for long-term intraocular pressure control after trabeculectomy. Surgical site fibrosis and excessive extracellular matrix production are common causes of trabeculectomy failure, mediated by several growth factors. We aimed to evaluate the levels of five growth factors and their correlation with trabeculectomy outcomes in patients with primary open-angle glaucoma (POAG).

Methods

We collected aqueous humor samples intraoperatively from patients with POAG who underwent trabeculectomy and measured the concentrations of transforming growth factor-β (TGF-β), acidic fibroblast growth factor (aFGF), insulin-like growth factor-1, vascular endothelial growth factor, and platelet-derived growth factor using multiplexed immunoassay kits. Intraocular pressure was measured with Goldmann applanation tonometry at 1 week and at 1, 3, 6, 12, 18, and 24 months after trabeculectomy. We allocated the eyes based on surgical outcome into a success or failure group.

Results

Significantly high levels of aFGF and TGF-β were observed in the failure group (both P < 0.0001) and were significant risk factors for trabeculectomy outcomes. Higher success rates were observed over the 24-month follow-up period in eyes with low aFGF and TGF-β levels compared to eyes with high levels (P = 0.0031 and P = 0.0007, respectively). The levels of TGF-β were significantly positively correlated with aFGF.

Conclusions

In POAG patients, high aFGF and TGF-β levels were significant risk factors for trabeculectomy failure.

Translational Relevance

Modulation of aFGF and TGF-β expression may have potential clinical applications after filtration surgery.

Animal models and drug candidates for use in glaucoma filtration surgery: A systematic review

Glaucoma, a degenerative disease of the optic nerve, is the leading cause of irreversible blindness worldwide. Currently, there is no curative treatment. The only proven treatment is lowering intraocular pressure (IOP), the most important risk factor. Glaucoma filtration surgery (GFS) can effectively lower IOP. However, approximately 10% of all surgeries fail yearly due to excessive wound healing, leading to fibrosis. GFS animal models are commonly used for the development of novel treatment modalities. The aim of the present review was to provide an overview of available animal models and anti-fibrotic drug candidates. MEDLINE and Embase were systematically searched. Manuscripts until September 1st^, 2021 were included. Studies that used animal models of GFS were included in this review. Additionally, the snowball method was used to identify other publications which had not been identified through the systematic search. Two hundred articles were included in this manuscript. Small rodents (e.g. mice and rats) are often used to study the fibrotic response after GFS and to test drug candidates. Due to their larger eyes, rabbits are better suited to develop medical devices. Novel drugs aim to inhibit specific pathways, e.g. through the use of modulators, monoclonal antibodies, aqueous suppressants or gene therapy. Although most newly studied drugs offer a higher safety profile compared to antimetabolites, their efficacy is in most cases lower when compared to MMC. Current literature on animal models and potential drug candidates for GFS were summarized in this review. Future research should focus on refining current animal models (for example through the induction of glaucoma prior to undertaking GFS) and standardizing animal research to ensure a higher reproducibility and reliability across different research groups. Lastly, novel therapies need to be further optimized, e.g. by conducting more research on the dosage, administration route, application frequency, the option of creating combination therapies, or the development of drug delivery systems for sustained release of anti-fibrotic medication.

Local Delivery of Pirfenidone by PLA Implants Modifies Foreign Body Reaction and Prevents Fibrosis

Peri-implant fibrosis (PIF) increases the postsurgical risks after implantation and limits the efficacy of the implantable drug delivery systems (IDDS). Pirfenidone (PF) is an oral anti-fibrotic drug with a short (<3 h) circulation half-life and strong adverse side effects. In the current study, disk-shaped IDDS prototype combining polylactic acid (PLA) and PF, PLA@PF, with prolonged (~3 days) PF release (in vitro) was prepared. The effects of the PLA@PF implants on PIF were examined in the rabbit ear skin pocket model on postoperative days (POD) 30 and 60. Matching blank PLA implants (PLA⁰) and PLA⁰ with an equivalent single-dose PF injection performed on POD0 (PLA⁰+injPF) served as control. On POD30, the intergroup differences were observed in α-SMA, iNOS and arginase-1 expressions in PLA@PF and PLA⁰+injPF groups vs. PLA⁰. On POD60, PIF was significantly reduced in PLA@PF group. The peri-implant tissue thickness decreased (532 ± 98 μm vs. >1100 μm in control groups) approaching the intact derma thickness value (302 ± 15 μm). In PLA@PF group, the implant biodegradation developed faster, while arginase-1 expression was suppressed in comparison with other groups. This study proves the feasibility of the local control of fibrotic response on implants via modulation of foreign body reaction with slowly biodegradable PF-loaded IDDS.